The idea that human behavior is guided by highly specific innate knowledge has passed its sell-by date. The interesting scientific questions do not encompass either "instinct" or "innate."

This is true for a number of reasons. First, there is never a period in the development of any individual, from their gamete stage to adulthood when they are not being affected by their environment. It is misguided therefore to think that newborns of any species only begin to learn from their environment when they are born. Their cells have been thoroughly bathed in their environment before their parents mated—a bath whose properties are determined by their parents' behavior, environment, and so on. The effects of the environment on development are so numerous, unstudied, and untested in this sense that we currently have no basis for distinguishing environment from innate predispositions or instincts.

Another reason for doubting the usefulness of terms like "insinct" and "innate" is that many things that we believe to be instinctual can change radically when the environment changes radically, even aspects of the environment that we might not have thought relevant. For example, in 2004 a group of scientists carried out experiments on rats in a low-gravity environment of earth orbit. What they discovered was that the self-righting (roughly, the way in which they come to their feet) routine that many had thought to be instinctual was ineffective in low gravity. But the rats didn't simply fail to self-right. They 'invented' a new strategy that worked while they were weightless. They showed behavioral flexibility where none had previously been expected.

In any case, the strongest reason for retiring instinct and innate from scientific thought is the devil of the details, which shows them to be, well, useless. For example, here is a partial list of possible definitions of 'innate' (borrowing from work by Matteo Mameli):

a trait is innate if it is not acquired; a trait is innate if it is present at birth; a trait is innate if it reliably appears during a particular, well-defined stage of life; a trait is innate if it is genetically determined; a trait is innate if it is genetically influenced; a trait is innate if it is genetically encoded; a trait is innate if its development doesn't involve the extraction of information from the environment; a trait is innate if it is not environmentally induced; a trait is innate if it is not possible to produce an alternative trait by means of environmental manipulations; a trait is innate if all environmental manipulations capable of producing an alternative trait are abnormal; a trait is innate if all environmental manipulations capable of producing an alternative trait are statistically abnormal; a trait is innate if all environmental manipulations capable of producing an alternative trait are evolutionarily abnormal; a trait is innate if it is highly heritable; a trait is innate if it is not learned; a trait is innate if (i) the trait is psychologically primitive and (ii) the trait results from normal development; a trait is innate if it is generatively entrenched in the design of an adaptive feature; a trait is innate if it is environmentally canalized, in the sense that it is insensitive to some range of environmental variation; a trait is innate if it is species-typical; a trait is innate if it is pre-functional; etc.

All of these definitions have been shown to be inadequate.

But let's suppose that we can find a workable definition of instinct or innate. We would still not be ready to use these terms. The reason is that we cannot attribute something to the human genotype without some evolutionary account of how it might have gotten there. And such an account would have to offer a scenario by which the trait could have been selected. To do this we would need information about the extent and character of variation in ancestral forms as well as differential survivorship and reproduction of those forms. To know how something was selected, however, we need to know something about the ecology under which the selection took place, such as an answer to questions like what were/are the ecological factors that explain the innate trait, either in the biological or social or other abiotic environment? Next, to use instinct or innate we would need to know how the traits could be passed on to subsequent generations. There should be a correlation between phenotypic traits of parents and offspring greater than chance. Then we would need to know about the population structure during the time of selected. Any evolutionary biologist also knows that we must have information concerning population structure, gene flow and the environment leading to the diffusion of the trait.

We do not know the answers to these questions. We are in no position at present to know the answers. And we will never be able to know some of the answers. Therefore, there simply is no utility to the terms instinct and innate. Let's retire these terms so the real work can begin.